DESCRIPTION (provided by applicant Each year, roughly 30,000 youth exit the foster care system due to aging out at age 18, losing access to support services while also becoming fully responsible for their own financial, health, employment, and housing needs. Progressing from homes disproportionately high in neglect, maltreatment, and parental substance use, these emerging adults face independence with an increased likelihood of developing substance use disorders. Once removed from foster care, these youth have far less access to health services compared to their non- foster care peers. Moreover, substance use services offered within the foster care system are often difficult to access. The proposed pilot intervention study seeks to address these gaps in availability, accessibility, and use of substance use services for youth aging out of the foster care system. Computer- and mobile phone-based interventions have the capacity to provide evidence-based treatment content while reducing many of the barriers relevant to substance use service delivery for foster youth. The proposed study will begin a program of research to synthesize the benefits of these approaches in a way that addresses the needs of a vulnerable population with many barriers to care. More specifically, this project involves the development and pilot data collection of a preventive intervention (iHeLP) targeting the reduction of problematic substance use among foster youth who are aging out of care. Rooted in motivational interviewing, the transtheoretical model, and social cognitive theory, iHeLP is a one-time computerized screening and brief intervention (SBI), supplemented by six months of tailored text messaging based on participants' SBI results and subsequent fluctuations in their readiness to change. The goal of this pilot study is to obtain preliminary daa on acceptability, feasibility, and initial efficacy. Focus groups will be conducted in which twenty four 17-year old foster youth will provide qualitative feedback on the perceived utility, likelihoo of use, and preferences for the content, interface, and functionality of the proposed intervention components. Results will be used to modify the intervention content/format, which then will be delivered to sixteen foster youth in an open trial of iHeLP. Further alterations may result from the qualitative and quantitative results of the open trial. Finally, thirty youth will participate n a pilot randomized controlled trial, testing the efficacy of iHeLP against a contact-control conditio. The use of daily text messaging represents a novel method for delivering intervention boosters. Low-intensity, high-frequency interactions are a marked change from traditional interventions and have high potential for extending initial gains. In addition, tailoring of these messages through dynamic, text-based communication with participants is innovative. Given the potential of wide dissemination to multiple at-risk populations at low cost, the proposed study has high potential public health and clinical significance.